水体pH对尼罗罗非鱼生长、营养组成和肉质的影响

WATER pH ON GROWTH,NUTRIENT COMPOSITION AND FILLET QUALITY OF NILE TILAPIA(OREOCHROMIS NILOTICUS)

为研究水体pH对尼罗罗非鱼(Oreochromis niloticus)生长、营养组成和肉质的影响,实验设置低pH(Low pH:4)、对照(Control:7.2)和高pH(High pH:8.5)三个水体pH梯度,投喂初重为(1.9±0.1)g的尼罗罗非鱼10周,并测定其生长性能、血清生化指标、肌肉营养成分和肉质相关指标。结果显示,相较于对照组,高pH和低pH水环境造成尼罗罗非鱼的增重率显著降低(P<0.05),肝糖原累积显著增高(P<0.05),同时也造成血清中甘油三酯的含量显著降低(P<0.05)及肝功能指标血清谷草转氨酶、谷丙转氨酶的活性显著增高(P<0.05)。另外,高pH水环境导致尼罗罗非鱼脏体比和肌肉黏性显著降低(P<0.05),肌肉蒸煮损失、肌肉和血清中乳酸含量显著增高(P<0.05)。同时,高pH组罗非鱼肌肉的PUFA,特别是n-3 PUFA的相对含量显著提高(P<0.05),肌肉脂肪酸营养价值得到提升。而低pH水环境则会造成罗非鱼的脏体比和饲料系数显著提高(P<0.05),及肌肉弹性的显著降低(P<0.05)。综上所述,尽管高pH水环境会使罗非鱼肌肉中n-3 PUFA含量有所提高,但是整体来看,高或低pH水环境均不利于尼罗罗非鱼的健康生长和肌肉品质的提升。

To investigate the effects of water pH on the growth,nutrient composition and fillet quality of Nile tilapia(Oreochromis niloticus),three groups(low pH,control and high pH)were set with pH levels 4.0,7.2 and 8.5,respec-tively,for 10 weeks trial,and then sample were collected for assessing the growth,serum biochemical parameters,muscle nutritional composition and fillet quality related parameters.The results showed that the high and low water pH caused a significant decrease in the weight gain and the content of serum triglycerides of Nile tilapia(P<0.05),and a significant increase in liver glycogen accumulation and the activities of serum aspartate aminotransferase and alanine aminotransferase(P<0.05).In addition,high water pH resulted in a significant decrease in viscerosomatic index and muscle adhesiveness of Nile tilapia(P<0.05),but a significant increase in the muscle cooking loss,muscle lactic acid content and serum lactic acid content(P<0.05).Moreover,the relative content of muscle PUFA,especially n-3 PUFA,increased significantly in the high pH group(P<0.05),indicating the nutritional value of muscle was improved.The low water pH resulted in a significant increase in the viscerosomatic index and feed conversion rate of Nile tilapia(P<0.05),and a significant decrease in muscle springiness(P<0.05).In conclusion,in addition to increasing the muscle n-3 PUFA content,neither high nor low water pH is suitable for the healthy growth and high flesh quality of Nile tilapia.